US4101866A - Marine detector spread having arrays of different lengths - Google Patents

Marine detector spread having arrays of different lengths Download PDF

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Publication number
US4101866A
US4101866A US05/715,762 US71576276A US4101866A US 4101866 A US4101866 A US 4101866A US 71576276 A US71576276 A US 71576276A US 4101866 A US4101866 A US 4101866A
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United States
Prior art keywords
array
detectors
arrays
seismic
seismic energy
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/715,762
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English (en)
Inventor
William H. Ruehle
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ExxonMobil Oil Corp
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Mobil Oil Corp
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Publication date
Application filed by Mobil Oil Corp filed Critical Mobil Oil Corp
Priority to US05/715,762 priority Critical patent/US4101866A/en
Priority to NZ184621A priority patent/NZ184621A/xx
Priority to NO772509A priority patent/NO145859C/no
Priority to MX170048A priority patent/MX145468A/es
Priority to GB32757/77A priority patent/GB1588462A/en
Priority to DE2735523A priority patent/DE2735523C2/de
Priority to EG482/77A priority patent/EG13081A/xx
Priority to AU27923/77A priority patent/AU510113B2/en
Priority to JP9756677A priority patent/JPS5323673A/ja
Priority to FR7725178A priority patent/FR2362404A1/fr
Priority to BR7705474A priority patent/BR7705474A/pt
Priority to CA284,868A priority patent/CA1082346A/en
Priority to DK366377A priority patent/DK366377A/da
Priority to NL7709164A priority patent/NL7709164A/xx
Application granted granted Critical
Publication of US4101866A publication Critical patent/US4101866A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/16—Receiving elements for seismic signals; Arrangements or adaptations of receiving elements
    • G01V1/20—Arrangements of receiving elements, e.g. geophone pattern

Definitions

  • This invention relates to seismic exploration and, more particularly, to a string of detectors having array lengths with improved response for the geology of the area being explored, for the offset distance from the seismic source to the array, and for the reflection time on the seismograms of reflections from formations of interest.
  • the invention is primarily useful in marine seismic exploration but can also be used for seismic exploration on land.
  • the lengths of the seismic detector arrays are changed to achieve the best response for the geology of the area being explored, for the offset distance between the seismic source and the detector array and for the arrival time of reflections from formations of interest.
  • a compositor combines the outputs of adjacent detectors in a string to form detector arrays of various lengths. These lengths are changed so that each array has the maximum length possible, such that the amplitude response of the array is within the pass band.
  • the seismic detectors are positioned much closer to the source than was previously done in the prior art.
  • the towing cable for the detectors forms an arc from the stern of the towing boat down to a depth at which the detector spread extends substantially horizontally.
  • detectors have been used only on the horizontally extending portion of the string. Because of this, the closest detector arrays to the source frequently have a long offset distance from the source. It is desirable to have short offset distances to record reflections from near surface formations.
  • detectors are positioned on the arcuate portion of the cable which is in front of the horizontally extending portion. These detector arrays are relatively close to the source and seismograms from these arrays can be used for exploration of near surface formations.
  • FIG. 1 depicts a portion of the detector spread together with the marine vessel and compositor
  • FIG. 2 shows one example of a detector spread in accordance with this invention
  • FIG. 3 depicts the period of a seismic pulse
  • FIG. 4 depicts the time ⁇ T
  • FIG. 5 shows the amplitude response of an array.
  • FIG. 1 shows a marine vessel 10 towing a cable 11 with a long linear detector spread.
  • a plurality of hydrophones 12, 13, 14 and others are included in the cable 11 at approximately equally spaced intervals.
  • the hydrophones detect reflections of seismic energy from a periodic source which is not shown in FIG. 1.
  • This source preferably is a linear array of air guns as described in the Ruehle pending application previously identified.
  • the hydrophones 12, 13 and 14 are on the arcuate portion of the cable 11 which is in front of the horizontally extending portion.
  • the distance from the seismic source to the end of this arcuate portion, which distance is noted by the arrow designated 15, may be on the order of 800 to 1,000 feet.
  • the hydrophones on the arcuate portion are used, thereby producing seismograms from detectors with a reduced offset distance from the source. These short offset seismograms are particularly useful for identifying reflections from near surface formations.
  • a compositor 16 combines the outputs of adjacent hydrophones to form hydrophone arrays having lengths which are multiples of the intervals between the hydrophones.
  • One compositor which is suitable for use is the DSS-V amplifier module supplied by Seismic Engineering Company. This module is described in "Digital Quality Seismic Streamer System" by W. H. Luehrmann, Paper No. OTC-2019, Sixth Annual Offshore Technology Conference, Houston, Texas, May 6-8, 1974.
  • This compositor amplifies the output from each hydrophone in the string and provides high level outputs at low impedances. Up to nine outputs from the string can be combined through a resistive summing network. This resistive summing network allows the outputs in each array to be weighted, one with respect to the other.
  • the outputs of the five hydrophones in the array 17 are combined in the compositor 16 to form one seismic trace which is recorded on the digital recorder 18.
  • the outputs from the three hydrophones in the array 19 are similarly combined, and the outputs from the four hydrophones in the array 20 are combined in the compositor 16.
  • the compositor also weights the outputs of the hydrophones so that the composite trace is the weighted sum of the outputs.
  • the compositor previously identified includes a resistive matrix for changing the relative amplitudes of the outputs of each hydrophone in the array.
  • FIG. 2 shows one example of how the outputs of all of the hydrophones in the string are combined to form arrays of different lengths.
  • the streamer has 312 hydrophone groups spaced at 12.5 meter centers. (Each group has 16 detectors at 0.67 m. spacing, but for clarity of description, a hydrophone group will hereafter be referred to as a hydrophone).
  • a total of 208 outputs are available at the boat.
  • Adaptors placed at the beginning and at the point 21 permit combining individual hydrophones to effect longer units.
  • the output of each trace is balanced to a common level. Up to 96 channels are digitally recorded.
  • the outputs of the first 104 hydrophones are brought directly to the compositor on the boat. Beyond the adaptor at 21, the outputs of the last 208 hydrophones are combined in pairs before they are brought back to the boat.
  • the weighting for the traces ahead of the adaptor 21 is as follows:
  • N 7 -- 0.3, 0.78, 0.9, 1, 0.9, 0.78, 0.3
  • n 5 -- 0.3, 0.75, 1, 0.75, 0.3
  • n 3 -- 1, 1, 1 (unity)
  • N 4 -- 1, 1, 1, 1 (unity)
  • the weighting for the traces behind the adaptor 21 is unity.
  • ⁇ is the period of the seismic pulse.
  • FIG. 3 depicts a seismic pulse and shows its period.
  • FIG. 4 depicts a reflected seismic wave striking an array of six detectors.
  • ⁇ T is the time required for a seismic pulse to travel from the point 22 to the detector 23. Stated another way, it is the time required for a seismic pulse to travel from the plane wave front at a point where it strikes a detector at one end of the array to the detector at the other end of the array.
  • the amplitude response of a linear array of detectors is given by: ##EQU2## This response is shown in FIG. 5.
  • the array has the longest possible length such that the amplitude response is in the band where ⁇ T/ ⁇ ⁇ 1.
  • the length of the array is chosen so that the response falls in the cross-hatched area of FIG. 5.
  • the desired band is defined by values of ⁇ T/ ⁇ which are less than 0.46. That is,
  • the band defines L max in the following manner.
  • L max The maximum length of an array, L max , is related to ⁇ T by the following:
  • the length of each array is a function of the period ⁇ and moveout ⁇ t of the seismic reflections. These in turn are dependent upon the geology of the formation being explored and upon the offset distance between the source and the center of the array. Specifically, the moveout per unit distance is determined from: ##EQU3##
  • H the horizontal distance between the source and receiver.
  • the approximate acoustic velocity, dip and reflection time of formations of interest are known to the geophysicist, either by prior exploration or by simple approximation.
  • the period of the seismic wave is also approximately known for varying depths or reflection times.
  • ⁇ is 0.025 from 0 to 2 secs. and 0.040 from 2.0 to 4.0 seconds.
  • the band can be made less than the point of maximum slope on the response curve.
  • This point of maximum slope is indicated by the reference numeral 30 in FIG. 5. It is a value of ⁇ T/ ⁇ ⁇ 0.68. This point of maximum slope can be used to separate primary and multiple reflections on the response curve introducing a multiple reflection suppression.
  • the invention is applicable to land systems using a cable similar to the string of hydrophones hereinbefore described.
  • One additional modification is required. Trace weighting and combining is distance dependent. The length of the arrays for land shooting will depend upon the noise characteristics measured in the area of application.

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  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • Remote Sensing (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
US05/715,762 1976-08-18 1976-08-18 Marine detector spread having arrays of different lengths Expired - Lifetime US4101866A (en)

Priority Applications (14)

Application Number Priority Date Filing Date Title
US05/715,762 US4101866A (en) 1976-08-18 1976-08-18 Marine detector spread having arrays of different lengths
NZ184621A NZ184621A (en) 1976-08-18 1977-07-11 Marine seismic detectors array length determination
NO772509A NO145859C (no) 1976-08-18 1977-07-14 Detektoranordning for bruk ved marine seismiske undersoekelser
MX170048A MX145468A (es) 1976-08-18 1977-07-29 Detector maritimo mejorado para la exploracion sismica
GB32757/77A GB1588462A (en) 1976-08-18 1977-08-04 Detector spread for marine seismic exploration
DE2735523A DE2735523C2 (de) 1976-08-18 1977-08-06 Detektoraufstellung für eine reflexionsseismische Untersuchung auf See
EG482/77A EG13081A (en) 1976-08-18 1977-08-14 Marine detector spread having arrys of different lenghts
AU27923/77A AU510113B2 (en) 1976-08-18 1977-08-16 Marine detector spread having arrays of different lengths
JP9756677A JPS5323673A (en) 1976-08-18 1977-08-16 Method of earthquake detection having arrangement of detectors of different lengths and detector arrangement
FR7725178A FR2362404A1 (fr) 1976-08-18 1977-08-17 Dispositif detecteur sous-marin avec des files de longueurs diverses
BR7705474A BR7705474A (pt) 1976-08-18 1977-08-17 Conjunto de detectores e processo e dispositivo para exploracao sismica
CA284,868A CA1082346A (en) 1976-08-18 1977-08-17 Marine detector spread having arrays of different lengths
DK366377A DK366377A (da) 1976-08-18 1977-08-17 Detektorfordeling til marineseismiske undersoegelser samt fremgangsmaade til bestemmelse af fordelingen
NL7709164A NL7709164A (nl) 1976-08-18 1977-08-18 Detectorspreiding voor seismische zee-exploratie.

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US (1) US4101866A (ja)
JP (1) JPS5323673A (ja)
AU (1) AU510113B2 (ja)
BR (1) BR7705474A (ja)
CA (1) CA1082346A (ja)
DE (1) DE2735523C2 (ja)
DK (1) DK366377A (ja)
EG (1) EG13081A (ja)
FR (1) FR2362404A1 (ja)
GB (1) GB1588462A (ja)
MX (1) MX145468A (ja)
NL (1) NL7709164A (ja)
NO (1) NO145859C (ja)
NZ (1) NZ184621A (ja)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4227246A (en) * 1978-11-06 1980-10-07 Vaughan Iii Warren T Multi-parameter measurement system for fluids
WO1982000365A1 (en) * 1980-07-24 1982-02-04 Moore N High resolution,marine seismic stratigraphic system
US4353121A (en) * 1980-07-24 1982-10-05 Fairfield Industries, Inc. High resolution, marine seismic stratigraphic system
US4467459A (en) * 1982-01-04 1984-08-21 Texaco Inc. Seismic method improving signal-to-noise ratio
US5148406A (en) * 1989-05-31 1992-09-15 Geco A.S. Method for simultaneous collection of seismic data from shallow and deep targets
US6791901B1 (en) * 1998-09-16 2004-09-14 Schlumberger Technology Corporation Seismic detection apparatus and related method
US20110176384A1 (en) * 2010-01-15 2011-07-21 Cggveritas Services Sa Method and Device for Processing Seismic Data
US8451682B2 (en) 2010-06-10 2013-05-28 Cggveritas Services Sa Method and apparatus for deghosting seismic data
US8531912B2 (en) 2010-01-15 2013-09-10 Cggveritas Services Sa Method and device to acquire marine seismic data
US8593904B2 (en) 2010-10-14 2013-11-26 Cggveritas Services Sa Method and device to acquire seismic data
AU2014201114B2 (en) * 2010-06-10 2014-07-31 Cggveritas Services Sa Method and apparatus for deghosting seismic data
AU2014203167B2 (en) * 2010-10-14 2016-07-21 Cggveritas Services Sa Method and device to acquire seismic data

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0066423B1 (en) * 1981-05-29 1988-01-13 Britoil Plc Method of determining the signatures of arrays of marine seismic sources, and of accumulating data for use in such methods
JPS5885904U (ja) * 1981-12-04 1983-06-10 富士ロビン株式会社 噴気式土壌改良機
US4737937A (en) * 1987-03-27 1988-04-12 Mobil Oil Corporation Marine seismic streamer employing variable hydrophone density

Citations (8)

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Publication number Priority date Publication date Assignee Title
US3096846A (en) * 1958-12-31 1963-07-09 Western Geophysical Co Method and apparatus for seismographic exploration
US3335401A (en) * 1966-01-07 1967-08-08 Mobil Oil Corp Noise-filtered detection of marine seismic signals
US3400783A (en) * 1966-12-27 1968-09-10 Mobil Oil Corp Centroid spaced seismic transducer array
US3430193A (en) * 1967-09-05 1969-02-25 Phillips Petroleum Co Seismic signal interpretation
US3613071A (en) * 1969-12-24 1971-10-12 Petty Geophysical Eng Co Simultaneous dual seismic spread configuration for determining data processing of extensive seismic data
US3863201A (en) * 1973-05-29 1975-01-28 Amoco Prod Co Seismometer arrays using operational amplifiers
US3887897A (en) * 1973-07-23 1975-06-03 Texas Instruments Inc System for changing seismic detection array lengths
US4011539A (en) * 1975-12-22 1977-03-08 Texaco Inc. Seismic detector arrays

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Publication number Priority date Publication date Assignee Title
US3747055A (en) * 1971-06-16 1973-07-17 Texaco Inc High resolution shooting with space domain filtering
US3719924A (en) * 1971-09-03 1973-03-06 Chevron Res Anti-aliasing of spatial frequencies by geophone and source placement
FR2156991A5 (ja) * 1971-10-13 1973-06-01 Commissariat Energie Atomique
US3852708A (en) * 1972-01-24 1974-12-03 Chesapeake Instr Corp Multiple element phased array with shaded sub-element groups

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3096846A (en) * 1958-12-31 1963-07-09 Western Geophysical Co Method and apparatus for seismographic exploration
US3335401A (en) * 1966-01-07 1967-08-08 Mobil Oil Corp Noise-filtered detection of marine seismic signals
US3400783A (en) * 1966-12-27 1968-09-10 Mobil Oil Corp Centroid spaced seismic transducer array
US3430193A (en) * 1967-09-05 1969-02-25 Phillips Petroleum Co Seismic signal interpretation
US3613071A (en) * 1969-12-24 1971-10-12 Petty Geophysical Eng Co Simultaneous dual seismic spread configuration for determining data processing of extensive seismic data
US3863201A (en) * 1973-05-29 1975-01-28 Amoco Prod Co Seismometer arrays using operational amplifiers
US3887897A (en) * 1973-07-23 1975-06-03 Texas Instruments Inc System for changing seismic detection array lengths
US4011539A (en) * 1975-12-22 1977-03-08 Texaco Inc. Seismic detector arrays

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4227246A (en) * 1978-11-06 1980-10-07 Vaughan Iii Warren T Multi-parameter measurement system for fluids
WO1982000365A1 (en) * 1980-07-24 1982-02-04 Moore N High resolution,marine seismic stratigraphic system
US4353121A (en) * 1980-07-24 1982-10-05 Fairfield Industries, Inc. High resolution, marine seismic stratigraphic system
US4467459A (en) * 1982-01-04 1984-08-21 Texaco Inc. Seismic method improving signal-to-noise ratio
US5148406A (en) * 1989-05-31 1992-09-15 Geco A.S. Method for simultaneous collection of seismic data from shallow and deep targets
US6791901B1 (en) * 1998-09-16 2004-09-14 Schlumberger Technology Corporation Seismic detection apparatus and related method
US8792299B2 (en) 2010-01-15 2014-07-29 Cggveritas Services Sa Method and device for processing seismic data
US20110176384A1 (en) * 2010-01-15 2011-07-21 Cggveritas Services Sa Method and Device for Processing Seismic Data
US8811112B2 (en) 2010-01-15 2014-08-19 CGGVeritas Serivices SA Method and device for processing seismic data
US9696443B2 (en) 2010-01-15 2017-07-04 Cgg Services Sas Method and device for processing seismic data
US8531912B2 (en) 2010-01-15 2013-09-10 Cggveritas Services Sa Method and device to acquire marine seismic data
US8456951B2 (en) 2010-06-10 2013-06-04 Cggveritas Services Sa Method and apparatus for deghosting seismic data
US8792296B2 (en) 2010-06-10 2014-07-29 Cggveritas Services Sa Method and apparatus for deghosting seismic data
AU2014201114B2 (en) * 2010-06-10 2014-07-31 Cggveritas Services Sa Method and apparatus for deghosting seismic data
US8451682B2 (en) 2010-06-10 2013-05-28 Cggveritas Services Sa Method and apparatus for deghosting seismic data
US9784868B2 (en) 2010-06-10 2017-10-10 Cgg Services Sas Method and apparatus for deghosting seismic data
US8593904B2 (en) 2010-10-14 2013-11-26 Cggveritas Services Sa Method and device to acquire seismic data
AU2014203167B2 (en) * 2010-10-14 2016-07-21 Cggveritas Services Sa Method and device to acquire seismic data
US9383470B2 (en) 2010-10-14 2016-07-05 Cgg Services Sa Method and device to acquire seismic data
US9134446B2 (en) 2010-10-14 2015-09-15 Cggveritas Services Sa Method and device to acquire seismic data

Also Published As

Publication number Publication date
NL7709164A (nl) 1978-02-21
FR2362404A1 (fr) 1978-03-17
AU2792377A (en) 1979-02-22
DE2735523A1 (de) 1978-04-20
NO145859B (no) 1982-03-01
BR7705474A (pt) 1978-07-04
AU510113B2 (en) 1980-06-05
NO145859C (no) 1982-06-09
NZ184621A (en) 1981-11-19
NO772509L (no) 1978-02-22
DE2735523C2 (de) 1987-03-26
JPS5323673A (en) 1978-03-04
DK366377A (da) 1978-02-19
EG13081A (en) 1980-10-31
CA1082346A (en) 1980-07-22
FR2362404B1 (ja) 1984-05-25
GB1588462A (en) 1981-04-23
MX145468A (es) 1982-02-19

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